Tokkai Hei 9-070104 published by the Japanese Patent Office in 1997 discloses a so-called parallel hybrid vehicle drive device wherein drive wheels are joined to an engine and a motor/generator via a continuously variable transmission. The motor/generator is driven as a motor when power is supplied from a battery, and supplies a rotation torque to the drive wheels. On the other hand when a rotation torque is input from the drive wheels, it performs regenerative braking wherein it generates power and charges the battery, while exerting a brake force on the drive wheels due to the rotation resistance.